Myeloid-derived suppressor cells promoted autologous B cell proliferation in rheumatoid arthritis / 北京大学学报(医学版)

Objective:To investigate the effect of myeloid-derived suppressor cells (MDSC) on pro liferation of B lymphocytes in rheumatoid arthritis (RA) patients.Methods:The peripheral blood specimens were collected from 15 healthy adults and 38 RA patients who were divided into high disease activity group,medium activity group and low activity group according to their 28-joint disease activity score (DAS28).And the frequencies of MDSC were determined by flow cytometry.Then,B cells and MDSC were isolated by flow cytometry,respectively.B cells were labeled with carboxyfluorescein diacetate suecinimidyl ester (CFSE) and then were co-cultured with MDSC in the presence of 3 mg/L anti-CD40 antibody and 10 mg/L CpG,for 3 days.Flow cytometry was performed to investigate the proliferation of B cells.Results:MDSC expanded markedly in high disease activity patients (7.13％ ±2.17％) compared with medium (5.35％ ±-1.36％) and low disease activity patients (4.72％ ± 1.08％) or healthy controls (4.79％ ± 1.02％) (P ＜ 0.05),and there were no statistical differences between healthy controls,medium and low disease activity RA (P ＞ 0.05).Moreover,the frequencies of MDSC were positively correlated with the DAS28 (P ＜ 0.05).After co-culture,MDSC significantly promoted B cell proliferation (P ＜0.01).Conclusion:Our studies showed that MDSC expanded obviously in high disease activity RA patients,and their frequencies were positively correlated with the disease activities.Furthermore,MDSC could promote autologous B cell proliferation remarkably in vitro.These findings suggest that MDSC might be involved in RA pathogenesis through regulating B cell functions.

[Responses of winter wheat tillers at different positions to low temperature stress at stem elongation stage and their freezing resistance evaluation].

Taking two winter wheat cultivars Ji' nan 17 and Shannong 8355 as test materials, this paper measured the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and the malondialdehyde (MDA) and soluble protein contents in the functional leaves and sheaths of the tillers at different positions at stem elongation stage under low temperature stress, and then, the freezing resistance of the tillers was comprehensively evaluated by the methods of principal component analysis and cluster analysis. The results showed that under low temperature stress, the SOD, POD, and CAT activities in the functional leaves and sheaths of each tiller at stem elongation stage increased, but the MDA and soluble protein contents increased or decreased to some extent. By using principal component analysis and cluster analysis, the tillers of each cultivar were grouped into three kinds of freezing resistance type. For Ji' nan 17, the main stem, tiller I, and tiller II belonged to high freezing resistance type, the tiller III, tiller IV, and tiller I p belonged to medium freezing resistance type, and the tiller II p belonged to low freezing resistance type. For Shannong 8355, the main stem, tiller I, tiller II, and tiller III belonged to high freezing resistance type, the tiller IV and tiller I p belonged to medium freezing resistance type, and the tiller II p belonged to low freezing resistance type. It was concluded that the freezing resistance of the winter wheat tillers at different positions at stem elongation stage differed, with the lower position tillers being more resistant than the higher position tillers.